The T28E1 CGMC (Combination Gun Motor Carriage) was an experimental design to give the armored divisions mobile anti-aircraft support. It featured a 37mm M1 anti-aircraft gun and two Browning .50-calibre machine guns, on a rotating platform, mounted on an M3 half-track chassis. As well as giving armored units their own self-propelled anti-aircraft artillery (AAA or triple-A), the T28E1 can also provide additional infantry support, mowing down soft ground targets.